Question

I want to replace some words in text, but only on conditions as, for example, if each is surrounded by whitespace.

To do this, I use:

Regex rx = Regex(@"\s+" + word + @"\s+");
str = rx.Replace(str, word2);

In the end, I get spaces replaced as well (and all the other specified surroundings). How can this be bypassed?

Answer 1

You can use the \b anchor to match the boundary between a \w (alphanumeric) and a \W (non-alphanumeric) character.:

Debug.Assert(Regex.Match(word, "^\w+$").Success);

string result = Regex.Replace(input, @"\b" + word + @"\b", word2);